IS : 8683 - 1977 ReaKmed 1991) (( Reaffirmed 2002 ) Indian Standard METHODS OF TEST FOR RAW ACRYLONITRILE BUTADIENE ( First Reprint APRIL: 1997 ) RUBBER UIX 678.762.2 - 134.532 : 543 0 Copyright 1978 BUREAIJ OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002 Gr 6 July 1978 IS : 8683- 1977 ( Renffkmed 1991) Indian Standard METHODS OF TEST FOR RAW ACRYLONITRILE BUTADIENE Rubber Sectional Committee, PCDC 14 RUBBER Chairman SHRI LALIT MOHANJAMNADAS SHRI K. TOHN ANCHERI SHR; T. J. GEORGE (Alternate) Representing The Cosmos India Rubber Works Pvt Ltd, Bombay The Rubber Dealers' Association, Kottayam Members Ministry of Defence (DGI) SHRI A. K. BANDYOPADHAYA SHRI M. KUMARAN(Alternate) National Test House, Calcutta DR D. K. DAS SHRI A. GHOSH(Alternate) Ministry of Defence (R & D) SHRI S. L. GANDHI . SHRI ANIL AGARWAL (Alternate) Dunlop India Ltd, Calcutta SHRI S. B. GANGULI SHRI K. S. LOGANATHAN (Alternate) Madras Rubber Factory, Madras SHRI A. GEORGE JOHN National Rubber Manufacturers Ltd, Calcutta DR I. V. KRISHNAMURTI SHRI J. CHATTERJEE (Alternate) Indian Rubber Regenerating Co Ltd, Thana SHRI G. R. KA~ISHWAR SHRI A. R. KANTAK (Alternate) Thirumbadi Rubber Co Ltd, Mokkam SHRI P. K. MADHAVA MENON Association of Planters' of Kerala, Kottayam SHRI D. W. MCCRIRICK SHRI P. K. MENON (Alternate) All India Rubber Industries Association, Bombay DR K. N. MODAK SHRI B. B. SANCTANI (Alternate) Hindustan Latex Ltd, Trivandrum SHRI R. MURALEEDHARAN NAIR Bata India Ltd, Calcutta SHRI S. C. NANDY SHRI S. SIRCAR (Altekmte) Synthetics & Chemicals Ltd, Bombay SHRI M. M. PATEL SHRI A. D. BANDKAR(Alternate) The Arakkunnam Cooperative Rubber Marketing SHRI M. C. PAUL Society Ltd, Arakkunnam Directorate General of Technical Development, DR N. V. C. &o New Delhi SHRI G. R. INAMDAR(Alternate) The Plantation Corporation of Kerala Ltd, SHRI R. RAVEENADRAN Kottayam SHRI K. T. VARGHESE(Alternate) The Travancore Rubber & Tea Co Ltd, SHRI S. V. SARMA Trivandrum SHRI C. S. KRI~HNA~WAMY (Alternate) (Continued on page 2) CQ Copyr&ht BUREAU OF INDIAN 1978 STANDARDS This publication is- protected under the Indian coiyright Act (XIV of 1957) and reproduction in whole or in part by any means except with written permission of the publisher shall be deemed to be an infringement of copyright under the said Act. IS : 8683- 1977 (Continuedjkom page 1) SHR~ SUN~LI. SHAH SHRI K. N. GANESH (AZternate) SHRI K. C. SEKAR SHRI M. M. VA~GHE~E SHRI E. V. THOMAS Members Representing Petrochemicals Indian Jawabarnagar Corporation Ltd, SHRI G. ARUMUCAM (Alternate) Padinjarekara Agencies (Pvt) Ltd? Kottayam United Planters' Association of Southern India, Coonoor The Rubber Board, Kottayam Director General, IS1 (Ex-o&cio Member) SHRI G. JAGDISH DAS (Alternate) DR G. M. SAXENA, Director (Chem) Secretary SHR~SATISHCHANDER Deputy Director (P & C), IS1 Methods DR S. N. CHAKRAVARTY of Test Subcommittee, PCDC 14, : 1 convener Bayer (India) Ltd, Bombay Dr S. N. Chakravarty) SHRIA.K.BANDYOPADHAYA SHRI M. KUMARAN(Alternate) SHRI B. BANERJEE DR D. K. DAS SHKI A. GHOSH (Ahnate) SHRI K. N. GANESH SHRI R. R. PANDIT(Alternate to Members Ministry of Defence (DGI) Indian Rubber Manufacturers Research Association, Thana National Test House, Calcutta Petrochemicals Indian Jawaharnagar Corporation Ltd, DR Y. N. SHAHMA(Alternate) DR A. S. GHAG SHRI S. S. MOKA~HI(Alternate) SHRI C. S. INAMDAR SHRI PUL~NL. KINARIWALA (Alternate) SHRI G. R. KAVISHWAR SHRI A. R. KANTAK (Alternate) DR I. V. KRISHNAMURTI SHRIJ. CHATTERJEE (Alternate) SHRI K. S. LOGANATHAN SHRI A. SEN (Alternate) SHRI P. K. MADHAVA MENON SHRI M. M. PATEL SHRI H. C. CHOPRA (Alternate) SHRI N. S. NAGARAJA RAO Mindia Chemicals Ltd, Bombay The Cosmos India Rubber Works Pvt Ltd, Bombay Indian Rubber Regenerating Co Ltd, Bombay National Rubber Manufacturers Ltd, Calcutta Dunlop India Ltd, Calcutta The Thirumbadi Rubber Co Ltd, Mokkam Synthetics & Chemicals Ltd, Bombay L. G. Balakrishnan & Bros Ltd, Coimbatore SHRI P. S. BALAXJBRAMANIAN (Alternate) Padinjarekare Agencies (Pvt) Ltd, Kottayam SHRI K. C. SEKAR Hindustan Latex Ltd, Trivandrum Dk N. H. SIVARAMA~U~HNAN SHRI E. V. THOMAS Rubber Board, Kottayam DR A. P. KURIAKOSE (Alternate) Travancore Rubber & Tea Co Ltd, Trivandrum SHRI S. V. SARMA SHRI C. S. KRISHNA~WAMY (Alternate) 2 IIS : 8688 - 1977 Indian Standard METHODS OF TEST FOR RAW ACRYLONITRILE BUTADIENE RUBBER 0. 0.1 This Indian FOREWORD Standard was adopted by the Indian Standards Institution on 24 November 1977, after the draft finalized by the Rubber Sectional Committee had been approved by the Chemical Division Council. 0.2 In the preparation of this standard, the following publications: IS0 IS0 247-1976 Organization assistance has been derived of ash. from Rubber - Determination for Standardization. International and synthetic Organization extract. Inter- 289-1963 Determination of viscosity of natural International rubbers by shearing disk viscometer. for Standardization. 1407-1976 Rubber - Determination of solvent national Organization for Standardization. IS0 BS 1673: Part 7 : 1969 Methods of testing raw rubber and unvulcanized compounded rubbers, Part 7 : Chemical analysis of acrylonitrile butadiene rubbers (NBR). British Standards Institution. 0.3 In reporting the result of a test or analysis made in accordance with this standard, if the final value, observed or calculated, is to be rounded off, it shall be done in accordance with IS : 2-1960*. 1. SCOPE prescribes the methods of test for raw emulsion acrylonitrile butadiene rubbers for volatile matter (NBR : l), solvent extract (NBR : 2), organic acid content (NBR : 3), soap content (NBR : 4), total ash content (NBR : 5), combined acrylonitrile content (NBR : 6), solubility (NBR : 7), and Mooney viscosity (NBR : 8). 2. QUALITY 1.1 This standard OF REAGENTS and distilled water (see 2.1 Unless specified otherwise, pure chemicals IS : 1070-1977t) shall be employed in tests. NOTE- `Pure Chemicals' shall mean chemicals that do not contain impurities which affect the results of analysis. *Rules for rounding off numerical values (rtised). tSpecification for water for general laboratory use (sec0nc-f f&.+2). 3 IS : 8683 - 1977 3. METHOD BALES 3.1 Take OF TAKING OUT TEST PORTION FROM SAMPLE out a piece or pieces of rubber from the selected bale by cuts through the entire bale perpendicular to the surface of largest area of the bale. The total mass of the material shall be between 600 g and 1 500 g depending on the tests to be done. Using a tool similar to that shown in Fig. 1, obtain plugs of rubber by cutting through the bale. Do not use any lubricant with the tool to obtain piece or pieces of the material. If the material is not tested immediately, place it in a narrow airtight container of not more than twice the volume of the material or keep it wrapped in two layers of aluminium foil until required. -__-______ -------_____ All dimensions FIG. 1 in millimetres. SAMPLING TOOL IS : 8683 - 1977 [NBR : I] DETERMINATION 0. GENERAL OF VOLATILE (NBR :l) MATTER 0.1 Details of three methods, namely, Method A, Method B and Method C, In Method A, weighed test portion is passed through a laboratory are given. mill having heated rolls till a constant mass is obtained. In Method B, the test portion is heated above phosphorus pentoxide for 2 hours under vacuum and loss in mass determined. In Method C, a weighed sample of polymer is sheeted out on a Iaboratory mill, then placed in an oven and dried to constant mass. For polymers which are too tacky to be handled satisfactorily on a heated mill, Method C is most appropriate. 1. METHOD 1.1 Apparatus 1.1.1 Laboratory Mill A 1.2 ProcedureWeigh a test portion of about 500 g of the sample to the nearest 0.1 g. Pass the weighed material through a laboratory mill, with the rolls of the mill maintained at 100 to 105"C, and the distance between the rolls set at 0.50f0.05 mm. Repeatedly pass the rubber between the rolls for 4 minutes without allowing it to form a band and then cool and reweigh to the nearest 0.1 g. Pass the rubber between the rolls for further If the masses at the end of 4- and 6-minute 2 minutes and again weigh. periods are not within 0.1 g, continue passing for further periods of 2 minutes until constant mass is obtained. 1.3 Calculation Volatile where matter, percent M1-M2 by mass = 7 1 before drying, after drying. x 100 and MI = mass in g of the material L21, = mass in g of the material B 2. METHOD 2.1 Apparatus 2.1.1 2.1.2 Laboratory Mill Vacuum Oven test portion with a nip 20°C. The pentoxide 20 mmHg). of about 100 g to the nearest 0.1 g of 0.6 mm (friction ratio I : 1-I 1) sheet is cut into small cubes, which for 2 hours at 60°C and a pressure Cool and weigh to the nearest 2.2 Procedure - Weigh a and pass it through a mill having a roll temperature.of are placed above phosphorus of 2.6 kPa (approximately 0.01 g. 5 IS : 8683 - 1977 [NBR : I] 2.3 Calculation Volatile where matter, percent Ali --hZ by mass = d Lk?, before drying, after drying. x 100 and A4i = mass in g of the material Al, = mass in g of the material C 3. METHOD 3.1 Apparatus 3.1 .I Laboratory Mill 3.1.2 Forced-Circulation Oven 3.2 Procedure -L Roll a sample of material through a laboratory mill The temperature with the distance between the rolls set at 0.25 ho.05 mm. Weigh a test portion of about 250 g of of the rolls should not exceed 30°C. the sample to the nearest 0.1 g. Place the sheets in a forced-circulation oven set at 100&5X so that both surfaces of thesheet are exposed to the draft. Allow the sample to remain in the oven until the mass is constant to within 0.1 g. Usually 1 hour is sufficient for polymers containing not more than 1 .O percent moisture. 3.3 Calculation Volatile where matter, percent Ml-M, by mass = -M 1 x 100 Ml = mass in g of the material M, = mass in g of the material before drying, after drying. and 6 IS : 8683- 1977 [NBR :21 DETERMINATION 0. GENERAL OF SOLVENT EXTRACT (NBR : 2) 0.1 This method is intended to determine the amount of various organic materials used or formed in the production process of the rubber. By this method the residual amounts of organic acid and soap as well as antioxidant or stabilizer added are measured. 1. OUTLINE OF THE METHOD 1.1 A weighed test portion of the rubber is extracted with isopropyl alcohol The solvent is distilled off and the in a suitable extraction apparatus. residue is dried and weighed. 2. APPARATUS 2.1 Extraction Apparatus-The extraction apparatus is of the reflux type with the condenser placed immediately above the cup which holds the sample. The cup is situated in the vapour of the boiling solvent and is emptied by a siphon. The apparatus is of glass except in patterns where an extraction cup is suspended from the end of condenser and, in that case, The apparatus fits together without platinum wire is used for suspension. the use of cork, rubber or metal and in such a manner that loss of vapour during extraction does not exceed 20 percent of the extracting liquid. 2.1.1 Suitable types of apparatus are shown in Fig. 1. filter paper or nylon 2.2 Filter Paper or Cloth - Acid washed hardened cloth of open weave made from continuous filaments. 3. REAGENT 3.1 Isopropyl Alcohol - 4. PROCEDURE SeeIS : 2631-1976*. \ 4.1 Heat the rolls of the laboratory mill to 95f5"C and set the nip at 0.25 & 0.05 mm. Pass a sample portion of rubber between the rolls at least Cut sufficient rubber from the sheet to give a strip weighing 3 to six times. 5 g. Weigh the test portion to the nearest 0.01 g and roll in filter paper to form a loose cylinder from which the rubber cannot fall and such that the surfaces of the rubber are not in contact. 4.2 Place the rolI in the extraction cup of the extraction apparatus. Assemble the extraction apparatus and pour isopropyl alcohol into the extraction flask, a quantity sufficient to fill the extraction cup two or three times. Extract the test portion with hot solvent for a continuous period of 16-&0.5 hours at a rate of 10 to 20 changes of solvent per hour. *Specification for isopropyl alcohol (first revision). 7 IS : 8683 - I977 4.3 Distil extraction 0.001 g. [NBR : 21 the solvent from the extract in a weighed vessel preferably in an flask, dry the extract at lOO&Z"C, cool and weigh to the nearest 5. CALCULATION Solvent where M1 = mass in g of extraction M2 = mass in g of extraction flask and extract, flask, and extract, percent by mass = M,--M, M 3 x 100 M3 = mass in g of test portion. IS : 8683 - 1977 [NBR : 31 DETERMINATION 1. OUTLINE OF ORGANIC (NBR ACID CONTENT : 3) OF THE METHOD 1.1 Accurately weighed sample is extracted with isopropyl alcohol. The solvent used for extraction as well as the rinsings of the sample are transferred to a volumetric flask and made to a known volume. An aliquot of the solution is titrated to the first sodium hydroxide using m-cresol purple as indicator. 2. APPARATUS 2.1 Chemical 2.2 2.3 Balance 250 ml capacity. colour change with Conical Flask Burette - 25 ml capacity. Cylinder Flask Apparatus 100 ml capacity. 2.4 Measuring 2.5 2.6 Volumetric Extraction 250 ml capacity. 3. REAGENTS 3.1 Isopropyl Alcohol See IS : 2631-1976". 3.2 m-Cresol Purple Indicator-Dissolve 0.1 g of m-cresol purple in 100 ml of `ethyl alcohol or water and add 2.6 ml of 0.1 N sodium hydroxide solution. 3.3 Standard Sodium Hydroxide Solution 0.01 N. 4. PROCEDURE 4.1 Prepare a test portion and extract with 2-propanol as described in (NBR : 2). At the end of the extraction period pour the solution into a 250-ml volumetric flask; rinse the extraction flask with two or three 10-d portions of warm isopropvl alcohol and add to the main bulk of the solution. Make up to the graduation mark with isopropyl alcohol, cool to room temperature. Mix thoroughly. 4.2 Measure 100 ml of this solution into a conical flask, add six drops of m-cresol purple indicator and titrate with 0.01 N sodium hydroxide solution to the first colour change from yellow to purple-blue. Titrate also 100 ml of isopropyl alcohol as a blank determination. *Specification for isopropyl alcohol ( jirstrevision). 10 IS : 8683- 1977 [NBR : 31 5. CALCULATION Organic where VI = volume in ml of sodium hydroxide solution required for test portion, L'2 = volume in ml of sodium hydroxide solution required for the blank, N = normality of sodium hydroxide solution, A\f= mass in g of the test portion, and acid, percent (VI-V,) by mass = x .N x F x 2.5 M F = 28.4when organic acid is calculated = 34.6 when acid is to be calculated as stearic acid, and as rosin acid. 11 IS : 8683 - 1977 [NBR : 41 DETERMINATION 1. OUTLINE OF THE METHOD OF SOAP CONTENT (NBR : 4) 1.1 Rubber is extracted with isopropyl alcohol and a known portion of the extract is titrated with 0.05 N hydrochloric acid, using m-cresol purple as indicator, to the first colour change. From the mass of the test portion and the titration, the percentage of soap is calculated. 2. APPARATUS 2.1 Extraction 2.2 Volumetric 2.3 Burette 2.4 Conical 2.5 Measuring 3. REAGENTS 3.1 Zsoprgpyl 3.2 Hydrochloric Alcohol Acid See IS : 2631-1976". 0.05 N. Apparatus Flask 250 ml capacity. 25 ml capacity. Flask 250 ml capacity. 100 ml capacity. Cylinder 3.3 m-Cresol Purple 100 ml of ethyl alcohol solution. 4. PROCEDURE Indicator - Dissolve 0.1 g of m-cresol purple in or water and add 2.6 ml of 0.1 N sodium hydroxide 4.1 Prepare isopropyl alcohol extract as per the procedure given in 4.1 of NBR: 3. Measure exactly 100 ml of the solution and transfer into a 250-ml conical flask. Add six drops of m-cresol purple indicator and titrate with 0.05 N hydrochloric acid to the first colour change from purple blue to yellow. Titrate also 100 ml of the isopropyl alcohol as a `blank' determination. 5. CALCULATION Soap, where V, = volume in ml of hydrochloric portion; acid required for the test percent by mass = (v1-v2)x ~vxFx2.5 M *Specification for isopropyl alcohol (jirst Ire&ion). 12 IS : 8683- 1977 [NBR IT2 = : 41 .volume in ml of hydrochloric acid required for the blank; N = normality of hydrochloric acid; A4 = mass in g of the test portion; and F = = = 30.6 when soap is to be calculated as sodium stearate, 36.8 when the soap is to be calculated as sodium rosinate, and 38.4 when the soap is to be calculated as potassium rosinate. NOTE- Unless the exact composition of the soap is known, the value ofF will be purely arbitrary, and the figure obtained for the soap content only approximate. 13 IS : 8683 - 1977 [NBR : 51 DETERMINATION 0. GENERAL 0.1 Details given. of two methods, OF TOTAL (NBR : 5) ASH CONTENT namely, Method A and Method B, have been 1. METHOD A 1.1 Outline of the Method - A sample of the rubber is wrapped in filter paper and placed in a crucible which is then put directly into muffle furnThe ash is ace at 550&25"C, till all the carbonaceous matter is oxidized. weighed and calculated as a percentage of the sample taken for test. 1.2 -Apparatus 1.2.1 1.2.2 1.23 Crucible Mu@ silica or porcelain ashless, of capacity diameter. controlling device. 85 ml. Filter Paper Furnace 150 mm with temperature 1.3 Procedure 1.3.1 Heat the crucible to a temperature of 550&25X for about Weigh about 3 g of dried 30 minutes, cool and weigh to the nearest 1 mg. rubber to the nearest 1 mg. Roll the sample tightly in filter paper, place in the crucible and put the crucible in the muffle furnace at 550&25"C and immediately close the doors and vent. 1.3.2 Continue heating until the carbon is completely oxidized white ash is obtained. Cool and weigh to the nearest 1 mg, 1.4 Calculation Total where Ml = M, = M3 = 2. METHOD B mass in g of crucible mass in g of crucible, mass in g of crucible plus ash, and plus dry rubber. ash, percent LVlr - M, by mass = M 3 2 and a x 100 2.1 Outline of the Method - The rubber is first heated in a crucible over a low burner flame. When the volatile decomposition products have been expelled the crucible is transferred to a muffle furnace where it is heated until all carbonaceous matter is oxidized. IS : 8683 - 1977 [NRR : 51 2.2 Apparatus 2.2.1 2.2.2 2.2.3 2.3 Crucible-silica Muse or porcelain a central of capacity 85 ml. device. the crucible. Furnace -- with temperature controlling Asbestos Board-with hole to accommodate Procedure 2.3.1 Heat the crucible in muffle furnace to a temperature of 550&25"C Weigh about for about 30 minutes, cool and weigh to the nearest 1 mg. Rest 3 g of dried rubber to the nearest 1 mg and place in the crucible. the crucible in the hole of the asbestos board, and heat with a small bunsen flame so that the rubber does not inflame and no spurting or undue frothing occurs. 2.3.2 When the rubber has decomposed to a charred mass, increase the heat from the burner until the volatile decomposition products have been substantially expelled, and then transfer the crucible to a muffle furnace at a temperature of 550&25X. Continue heating until the carbon is Cool and weigh to the completely oxidized and a clean ash is obtained. nearest 1 mg. 2.4 Calculation Total where Ml = M, = M, = mass in g of crucible plus ash, mass in g of crucible, and mass in g of crucible plus dry rubber. ash, percent by mass = zg 3 2 x 100 15 IS : 8683 - 1977 [NBR : s] DETERMINATION OF COMBINED CONTENT (NBR : 6) METHOD ACRYLONITRILE 1. OUTLINE OF THE 1.1 The rubber is oxidized by heating with a mixture of potassium sulphate and concentrated sulphuric acid together with a catalyst, thereby converting nitrogen compounds into ammonium hydrogen sulphate, from which the The ammonia is removed by distillation after making the solution alkaline. liberted ammonia is absorbed in boric acid solution and titrated with standard acid. From this nitrogen determination the amount of combined acrylonitrile content in rubber is calculated. 2. APPARATUS 2.1 Semi-micro 2.2 Semi-micro borosilicate glass. 2.3 2.4 Burette Conical Kjeldahl Digestion Flasks 30 ml capacity. Kjeldahl Digestion Unit - with condenser tube of The capacity of distillation flask should be 80 to 100 ml. in 0.02 ml. as receiver for Kjeldahl distillate. 10 ml, graduated Flask - 100 ml capacity, 3. REAGENTS 3.1 Catalyst ,30 parts by mass of anhydrous Prepare a finely divided and intimate mixture of potassium sulphate, 4 parts of copper sulphate pentahydrate (CuSO,. 5H,O) and 1 part of selenium or 5 parts of sodium selenate decahydrate (NasSeO,. 1OHsO). Mixture 3.2 3.3 3.4 3.5 Sodium Hydroxide 10 M solution. Acid 98 percent m/m (36 N) solution. Concentrated Boric Acid Sulphuric Sulphuric 0.5 M solution. 0.1 N solution. g of may Acid - 3.6 Indicator Solution-Dissolve 0.1 g of methyl red and 0.05 methylene blue in 100 ml of 96 percent ethanol. This indicator deteriorate on storage and should be freshly prepared as required. 4. PROCEDURE 4.1 Weigh accurately about Add 0.65 dry Kjeldahl flask. sulphuric acid. Boil gently after the digest has become 0.1 g of dry rubber and place it in a clean g of catalyst mixture and 3 ml of concentrated and continue boiling for about half an hour a clear green liquid with no yellow tint. 16 IS : 8683 - 1977 [NBR : 61 Commence at the same time a blank determination using same quantities of reagents taken from the same containers as those used in testing the sample, and thereafter treat the test portion and blank determination similarly. Excess boiling, as indicated by a tendency for the digest to solidify on cooling, should be avoided, since this may lead to loss of nitrogen. 4.2 Boil water in the steam generator of the distillation unit and pass steam through the apparatus, including the receiver for 2 minutes. 4.3 Meanwhile, cool the Kjeldahl flask and its contents to room temperature, dilute with 10 ml of water and immediately transfer to the distillation flask at the conclusion of the steaming-out process. Rinse with three 3-ml portions of water to complete the transfer and drain as thoroughly as possible after each transfer. 4.4 Discard any distillate from the receiver of the distillation unit, add 10 ml of boric acid solution, two drops of indicator solution, and place the receiver under the condenser so that the end of the condenser dips below the surface of the acid. 4.5 From a measuring cylinder add 15 ml of 10 M sodium hydroxide solution to the distillation flask and drain well. Pass steam from the generator through the distillation flask for 10 to 12 minutes at such a rate that the final volume of the liquid in the receiver is about 70 ml. At the conclusion of the distillation, lower the receiver until the tip of the condenser is above the level of the acid, continue distilling for 1 minute longer and then rinse the end of the condenser into the distillate with a few millilitres of water. Immediately titrate the contents of the receiver with 0.1 N sulphuric acid. 5. CALCULATION Combined acrylonitrile by mass where Vr = V, = Jv = volume in ml of titrant used for test portion, volume in ml of titrant used for blank, normality of titrant, and mass in g of thesample taken. content, percent = (Vr-I',) xNxO.053 06 x 1oo M M = 17 IS: 8683-1977 [NBR:7] DETERMINATION (NRR 1. OUTLINE OF THE METHOD OF SOLUBILITY : 7) 1.1 A weighed amount of unmilled rybber is solvent for 24 hours at room temperature. The a weighed standard sieve of 150 micron aperture thoroughly washed with solvent, and the screen 2. REAGENT 2.1 Methyl Ethyl Ketone shaken with appropriate solution is poured through size, the insoluble material dried and reweighed. 3. APPARATUS 3.1 Bottle with Screw Cap 3.2 Sieve 150-micron approximately 250 ml to 300 ml capacity. wire. IS sieve made from non-corrodible Shaker 3.3 Dispersion 4. PROCEDURE Rolls or Mechanical 4.1 Weigh accurately about 0.1 g of raw unmilled rubber cut into small pieces, put it into the bottle and add 100 ml of methyl ethyl ketone. 4.2 Close the bottle tightly and allow to roll on dispersion rolls or shake slowly on mechanical shaker for 24 hours at room temperature. Decant the solution through 150-micron IS sieve which has been weighed to 0.1 mg and rinse the jar and the sieve with several portions of cold solvent making certain that all the insoluble gel is transferred to the sieve. When the soluble material has been completely washed from the sieve, place it in's vacuum oven at 120&5X for 30 minutes, cool in a desiccator and weigh to 0.1 mg. 5. CALCULATION Solubility, where Ml = M, = mass in g of the material mass in g of the insoluble used for the test, and gel collected on sieve. percent by mass = Ml-"s M 1 Xl00 18 IS : 8683 - 1977 [NBR : 81 DETERMINATION 1. OUTLINE OF MOONEY (NBR : 8) VISCOSITY OF THE METHOD 1.1 The test involves the application of a torque to a metal disk in a cylindriA number procal chamber filled with rubber under specified conditions. portional to the torque necessary to rotate the disk is taken as an index `of the viscosity of the rubber. 2. APPARATUS Disc Viscometer are a rotor, a hollow cylindrical die, a means for rotating the rotor, a means for indicating the torque required to rotate the rotor, and controls for maintaining the die at a The rotor and die cavity have the constant temperature (see Fig. I). dimensions given below : mm Rotor Rotor diameter thickness 38.10 &-O-O3 5.55 10.03 50.90*0.15 10.60 ho.03 TEMPERATURE MEASURING SP(TT 2.1 The essential parts of the Shearing Die cavity diameter Die cavity depth / GAUGE GLOCK FOR CLOSlNG THE CAVITY f PLAlC FIG.1 ESSENTIAL PARTSOF THE SHEARINGDISCVISCOMETER IS : 8683 - 1977 [NBR : 131 2.1.1 It is permissible to use a smaller rotor where high viscosity makes This small rotor should have the same thickness as the large this desirable. rotor but the diameter should be 30,48&0.03 mm. 2.1.2 Results obtained with the small rotor are not identical with those obtained with the large rotor. However, for the purposes of comparing rubbers or compounds, they lead to the same conclusions. 2.1.3 The die cavity (see Fig. 2) should preferably be formed from only two pieces of unplated hardened steel for improved heat transfer and have radial V-grooves on the flat surfaces to retard slipping. The grooves are spaced at 20" intervals, and extend from at least the 7 mm circle to the 47 mm circle; each groove forms a 90" angle in the die surface with the disector of the angle perpendicular to the surface and is 1 ,OO10.25 mm wide at the surface. 2.1.4 The die cavity (see Fig. 3) may alternatively be formed fi-om four pieces of steel with rectangular-section grooves (see Fig. 3A and 3Rj on the cavity surfaces to retard slipping. The grooves are 0.80+0,02 mm wide, DE OF THEGROOVES FIG. 2 RADIAL V-GROOVES OF DIE CAVITY 2c IS : 8683-1977 CENTRING PIN [NBR :8] FOR DETAILS OF GROOVES `0430 + .02-_ [o.30505 SECTION All dimensions XX in millimetres. FIG. 3A WALL PROFILE